Up until now there are described a number of antineoplastic drugs which interfere with the structure and function of microtubules in both interphase and mitotic cells. As most important compounds having said properties their may be named nocodazole, vinblastine, vincristine sulfate and cis-ethyl[4-[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3 -dioxolan-4-ylmethylthio]phenyl]carbamate, generically designated as tubulozole. The latter is described among other structurally similar compounds in U.S. Pat. No. 4,490,540 and is specifically described in Cancer research 45, 733-742 (1985), Invasion and Metastasis 5, 170-184 (1985) and Eur. J. Cancer Clin. Oncol. 1, 99-105 (1984) as a microtuble inhibitor useful in the treatment of neoplasms. The present C.sub.1-4 alkyl[4-[2-(4-C.sub.1-4 alkyloxyphenyl) -2(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-ylmethylthio]phenyl]carbamates differ from the known compounds by their alkyloxy substitution on the phenyl ring and specifically by their favourable antineoplastic properties.